With the new reorganization of the working groups within Commission V, there are significant interest in digital photogrammetry by all working groups within the Commission. The number of papers devoted to this subject in this Zurich Symposium is a clear evidence that computer vision techniques will be a major force in the automation of close-range photogrammetry in many traditional as well as new application areas. Within the new structure of the working groups, WG V/1 will have responsibility in areas related to the development and implementation of fully automated and real-time systems. More specifically, the terms of reference are as follows: 1. real-time vision systems for metric measurement; 2. near-real-time, but fully automated, vision systems with relaxed time constraints; 3. system hardware and software integration; and 4. demonstration of real-time and near-real-time systems in actual application environments.

An International Robomation/Intelligence (IRI) DX/VR Vision System and a PC/AT vision system are being used to conduct research on the application of vision systems for performing metric measurements in engineering construction and manufacturing. The IRI DX/VR system is a UNIX-based, multi-user program development workstation with a host computer that is capable of performing about 1 million instructions per second. The PC/AT system employs a Zenith 386 personal computer, two frame grabber boards to permit simultaneous imaging from two cameras, and MS-DOS operating system. Both systems are equipped with 512x512 CCD cameras. An expanding package of software is being developed to perform, on either vision system, many photogrammetric functions, including: camera calibration, image correlation, and feature matching. While the IRI system provides more speed in performing basic image processing operations, the PC system has the major advantage that a large library of commercial software is available for performing data analysis. Geometric distortion characteristics of both line-transfer and frame -transfer CCD cameras are being studied.

The Canadian contribution to the International Space Station "Freedom" is the Mobile Servicing System (MSS). The MSS (Figure 1.0) is a collection of robotic elements configured to support the assembly, maintenance and servicing of the space station. The major components of the MSS are: Ã‚Â° Space Station Remote Manipulator System (SSRMS): a large robotic manipulator arm with seven degrees of freedom used primarily for handling large objects on station including the capture and docking of the shuttle orbiter. Ã‚Â° Special purpose Dextrous Manipulator(SPDM): a smaller two arm robotic device capable of performing robotic servicing tasks requiring dexterity. Ã‚Â° Mobile Servicing Centre (MSC): a mobile base for the MSS from which the robotic manipulators can be operated remotely and used to transport payloads around station. Although these manipulators will usually be controlled directly or remotely by astronauts, a fundamental component of the MSS Control Equipment (MCE) is an Artificial Vision Unit (AVU), which will play a major role in both manual and automatic control of the manipulators and cameras. The baseline specification states that the AVU will support the rendezvous and proximity operations including payload tracking, payload capture and payload berthing3. In one mode, the AVU shall provide data to the astronaut operator in the form of textual and graphical displays. In another mode, the AVU data shall allow the closed loop control of MSS manipulators for these operations. The baseline also requires Fine Robotic Service tasks to be provided with machine vision support. This paper deals with some aspects of a program to develop the necessary machine vision technologies.

The US Federal Highway Administration and the Center for Mapping of The Ohio State University are developing a prototype mapping vehicle that integrates a stereo-vision system, a GPS receiver, and some other sensors, to automatically collect data of the environment of roads at highway speeds and store this information in a GIS. Thirty eight states and one Canadian province are sponsoring this effort together with NASA. In this paper we discuss the integration of the stereo-vision system with a GPS-receiver and an inertial system in a mobile workstation. The major task of the vision system is the acquisition and storage of digital image pairs once a second. The shutters of the camera are synchronized by the clock of the GPS receiver. The system will be calibrated by analytical methods using a testfield of control points. The offset between the GPS antenna and the vision system is determined by a rigorous bundle- and geodetic adjustment. Beside the storage of images the vision system is used for sequential triangulation of stereo pairs along the road, to bridge over areas without satellite signals. We also try to extract the edges of roads automatically and compute its width. As the construction of the prototype is presently ongoing, preliminary results and the configuration of the hardware are presehted.

Medical and industrial needs exist to track the position, volume and geometry of moving objects whose shapes change. Video imaging offers frame rates of sufficient frequency to support real-time sensing of fairly rapid changes in the real world. It is the processing of the video frames which represents the bottleneck in a "real- time" implementation. However, under certain limiting constraints, namely near-symmetry around a curved axis, real-time measure- ments are feasible with standard PC-based software to obtain 3-D positions, shape and volume of a moving and changing 3-D object. The paper describes a novel stereo-photogrammetric analysis system based on object silhouettes. Implementation involves the end-to-end system from video cameras to user interface and reporting of results. A medical application's scenario puts high demands on robustness and simplicity of the user interface, while operating in an entirely automated fashion. "Real-time" represents the need to process an image pair each 2 seconds. Accuracies of Ã‚Â±1% in dimension and 3% in volume are required and permit one to accept certain shortcuts in the photogrammetric approach.

Since 1975 lateral-effect photodiodes have been well-known opto-electronic sensors for the measurement of imaged light sources. They provide a simple evaluation of the image coordinates of the centroid of an imaged light source and have excellent dynamic characteristics. Due to the physical principle of these sensors the accuracy of 3D-measurement is greatly influenced by reflections and distortion causing large non-linearities. This paper describes investigations concernig the theoretical and experimental accuracy behaviour of a developed photogrammetric system equipped with lateral-effect photodiodes.

The new Working Group in Architecture and Archaeology was established as part of Commission V in 1988. However, this was not the start of Commission V involvement with Architectural and Archaeological Photogrammetry, as for a number of years we have had an "Associated" group.

Before the restoration of works of art we need to execute metric, qualitative and storic researches to acquire a deep knowledge of the object on which the opera- tion will be executed. We intend to expound and explain. the problems concerning metric surveys executed with the stereophotogrammetric method on particular "movable" works of art. These problems include: the acquisition of control points with the Wild-Leitz MiniRMS2000 system, the selection and definition of the essential lines of the stereoscopic mo- del, the transfer of acquired data to a CAD system, the processing to these data for the creation of thematic drawings or parallel views or for the separation of the object in parts, etc. We will produce surveys and processing of a painting on wood of the Maestro di S. Francesco (XIII century, m 4.90 x 3.54 x 0.15) and a polyptych of S.Antonio on a board and a frame also on wood painted by Piero della Francesca (XV century, m 4.10 x 2.00 x 0.12). Both of them are of the Soprintendenza ai Beni Architettonici Artistici Ambientali e Storici dell'Umbria - National Gallery of Perugia. We will also produce parts of a painted glass window of the Orvieto Cathedral apse.

The Laboratory of Photogrammetry of the University of Architecture in Venice is involved in a research program aimed to quantitative measurement with respect to reliable and precise informations. The walled city of Cittadella (one mile of medieval walls with four gates and thirty-two towers) will shortly go under a restoration program financed by the Italian Governement, the Veneto Region and the municipality of Cittadella. The question in point is to find the most suitable system to respond to a series of problems that different disciplines will raise which can be here only briefly summarized: 1 - archeological analysis will be concerned in determining the various periods of construction of the different "layers" of the wall; 2 - statical analysis and geodetical surveys will try to determine the quality of the intervention of restoration; 3 - chemical and physical measurements will ascertain the effect of erosion and deterioration of materials testing the most convenient procedures for future protection. For all these purposes a specific field of experiment has been recently set up where photogrammetry will be tested to combine "classical" expertise with the "new" approach of computer vision, 3D models and cost-benefit analysis.

ABSTRACT PADRAS,PASCO Archaeological DRAwing System, has recently evolved into two directions. The first direction of evolution is utilization of CAD system.The previous mobile type PADRAS system consisted of photo laboratory,portable analytical plotter and X-Y plotter in a microbus.By introducing AutoCAD system into analytical plotter(PADRAS-P3D) and total station surveying system(PADRAS-T3D), we have obtained real time 3D digitizers of a CAD system applied to drawing of archaeological research.Total station surveying system has realized on-line and real-time visualization of an archaeological site on a loptop PC display within the environment of AutoCAD. The second direction is related to connection between CAD system and Data Base system.PADRAS systems attach attributes to graphical features which are compatible to relational data base software(R:BASE PRO).Aiming to digital historical maps or Atlas,PADRAS system,as a whole, evolves out of an approach of Drawing System,Relational Data Base into a construction of Geographic Information System, utilizing new combination among photogrammetry,terrain surveying,CAD system, Data Base systems and Geographic Information System,such as ARC/INFO.

In the field of Maya research archaeological studies in architecture play an important part. In the case of Santa Rosa - XTAMPAK the influences of different cultural regions have to be traced. Structures like this situated in border areas, especially require exact surveying so that signficant archaeological assertions can be derived. For the main palace of this site a threedimensional digital architectural model was established, using geodetic-photogrammetric methods. Possibilities of visualization with the help of recently developed technology are shown by examples: certain details of the palace as well as an inner staircase have been digitally recorded. This certainly means considerable help for further study.

The practical application of analytical photogrammetry permits digital data being used in CAD systems such as AutoCAD. In the case of fire damaged buildings sometimes only small or partial examples of detail remain, but by combining photogrammetry and CAD this detail can be recorded and repeated to replicate the original design. This paper looks at some actual examples of analytical photogrammetry and CAD joining hands to help reconstruct some historic buildings including a famous Wren church in the City of London.

The state-of -the-art in sensor techniques for close-range photogrammetry is characterized by two major trends. In the field of photographic sensors reseau cameras are gradually superseding conventional metric systems and leading to camera systems of very high accuracy. Fully digital imaging systems are also advancing, and particular use is made of CCD cameras with standard video output. Higher resolutions can currently be only achieved if the object is recorded sequentially by a moving CCD sensor in the image space. Additional illumination devices and object targeting have to be involved in the photogrammetric recording process. Image recording systems are only one component of a total system. In order to judge the efficiency of the system the complete object recording and data processing procedure must be taken into account.

The geometrical accuracy of modern CCD sensors is typically better than 1/100 of the pixel period. For this reason CCDs are almost ideal tools for many optical metrology applications. Traditional video framegrabbers are ill suited for these applications because framegrabbers cannot acquire the video signals synchronously with the CCD's pixel clock. A universal CCD data acquisition system was developed, capable of digitizing video signals from almost any CCD camera, up to a speed of 20 MHz with either 8 or 10 bits of accuracy. Practical problems had to be solved for applications with standard CCIR CCD video cameras (560v x 600-800h resolution, 50 fields per second), and scientific high-resolution CCDs (1024v x 1024h resolution, 10-40 frames per second). The experimentally determined accuracy of the position of an object, measured with a CCD image sensor using 10-bit pixel- synchronous digitization is better than 1/100 of the pixel period, obtained by averaging many measurements. This experimental accuracy is not as good as the theoretical calculation of the precision indicates. The main reason for this are: pixel response non-uniformity, fabrication tolerances of the CCD sensor, non-ideal sampling of the video signal, and residual timing jitter in the pixel-synchronous sampling.

A newly developed imaging principle, two dimensional microscanning with Piezo-controlled Aperture Displacement (PAD), allows for high image resolutions. The advantages of line scanners (high resolu- tion) are combined with those of CCD area sensors (high light sensitivity, geometrical accuracy and stabi- lity, easy focussing, illumination control and selection of field of view by means of TV real-time imag- ing). A custom designed sensor, optimized for small sensor element apertures and color fidelity, elimi- nates the need for color filter revolvers or mechanical shutters and guarantees good color convergence. By altering the computer controlled microscan patterns, spatial and temporal resolution become interchange- able, their product being a constant. The highest temporal resolution is TV real-time (50 fields/sec), the highest spatial resolution is 2994 x 2320 picture elements (Pels) for each of the three color channels (28 MBytes of raw image data in 8 sec). Thus for the first time it becomes possible to take 35mm slide quali- ty, still color images of natural 3D scenes by purely electronic means. Nearly "square" Pels as well as hexagonal sampling schemes are possible. Excellent geometrical accuracy and low noise is guaranteed by sensor element (Sel) synchronous analog to digital conversion within the camera head. The cameras principle of operation and the procedure to calibrate the two-dimensional piezo-mechanical motion with an accuracy of less than 0.2[tm RMSE in image space is explained. Latter uses a fast algo- rithm to estimate the shift between image pairs with an accuracy of about 1/1000 Sel, based on greyvalue gradients modelled as second order polynomials. The remaining positioning inaccuracy may be further reduced by adaptively postprocessing the high-resolution images.

The small dimensions of the focal planes of solid-state sensors and the limited resolution of the pixel array decrease the potential applications of vision systems. Zoom lenses can enhance the flexibility and capabilities of vision systems by providing the user with continuous access to a full range of focal length settings without degrading geometric accuracy. The key to the use of such lenses lies in the inherent stability of array cameras. Preliminary test results showed that when the focal length setting of a zoom lens was changed, significant changes occurred in both the position of the principal point and lens distortion characteristics. However, these changes were found to be either linear or curvilinear over the entire range of zoom. Moreover, both the magnitude and pattern of the changes were found to be highly stable over a period of weeks. Thus, the results indicated that the changing interior geometry of zoom lens camera systems can be pre-calibrated and then applied during the measurement process. This paper reports on experimental results and distortion models using two zoom lenses with focal lengths ranging from 12.5mm to 75mm.

High resolution digital cameras have become an interesting tool in digital photogrammetry. At the Technical Uniyersity of Braunschweig, Department of Photogrammetry and Image Processing, several cameras, including the Reseau Scanning Camera, Videk Megaplus and the ProgRes 3000, have been under investigation for photogrammetric purposes. The different ways to achieve high resolutions are briefly described, as well as the method of investigation, including digital point measurement and testfield triangulation. The results are presented in the last part together with practical experiences made in camera handling.

During the recent years, the use of small format cameras, whether metric or nonÃ¢â‚¬â€metric, has flourished again, no doubt mainly due to the rapid development of the personal computers. In this paper the photogrammetric applicability of these cameras is reviewed, discussed and assessed. Special emphasis is given to their implementation in archaeological or architectural photogrammetry. Finally their prospects are investigated and a bold attempt is made to forsee their future.

In this paper, an analytical photogrammetric evaluation system, developed using off- the-shelf optical, mechanical and electronical components, will be introduced. The measurement of the diapositive (up to the format 24 x 24 cm') is based on two low- priced, hut precise x, y-positioning systems, driven by step motors via spindles. Stage positioning in comparator or model mode is provided by two trackballs. The software contains a special program for 3D representation of buildings. This paper reports on the possible increase in efficiency by using high resolution photography.

Since August 1988 the University of Bamberg works with the analytical photogrammetrical evaluation system ROLLEIMETRIC MR2 in the Institut of Ancient Monuments survey. As so far in this field measured drawings had been carried out by hand, it was to be evaluated if the photogrammetry would obtain sufficient results for the building research. Besides the low-cost equipment, the system provides the advantage of the possibility to be used by non-photogrammetrists. For the building research this is of great importance. With three examples it is shown that ROLLEIMETRIC MR2 is a useful tool in the building research and is demonstrated how important the cooperative work between photogrammetrist and the user of the drawings is for obtaining best results. The advantages and disadvantages of the System are discussed.

This paper outlines research being undertaken in the Civil Engineering Department at Leeds University, England, using a new, low-cost analytical photogrammetric plotter. The project, which is funded by the UK Science and Engineering Research Council ,involves the use of an MPS-2 desktop analytical plotting system, manufactured by Adam Technology of Australia, to produce architectural drawings and to monitor crack propagation in structures. Details are given of the working system which consists of metric and non-metric cameras, a personal computer, an interface to AutoCAD software and a rolling drum plotter. The areas of application being investigated are illustrated by studies of buildings and structures in the civil engineering laboratory of the University and around the Leeds area. The problems encountered are summarised and an assessment of the system is made. The paper concludes with a discussion of the progress of the research project and reviews the work still to be undertaken.

This work deals with the application of the collocation method to the control of the floor movements of the St.Marcus' Basilica in Venice. Results and prospects are examined and some graphic representation systems are proposed which make easy the reading and the interpretation of the movement itself.

A Rollei 6006 partial-metric camera was equiped with special objectives of 50 resp. 28 mm focal length to control and measure the surfaces of small sand-stone plates (complex research programme of the Ministry of Science and Technology of the FRG). The lenses were mounted in retro-position, a surface of the stone samples of 5 cm x 5 cm resp. 2.5 cm x 2.5 cm can be photographed. The depth of focus was 8 resp. 6 mm. An optical flat grid was used for the system calibration. The measurements were carried out by a Zeiss Planicomp C100. The standard deviation of eleva- tion after bundle adjustment was 16 m for the 50 mm-lens resp. 9 m for the 28 mm-lens. The planimetry was much better. Results of bundle adjustment will be shown and a CAD-evaluation will demonstrate the stone weathering.

The department of architectural photogrammetry of the Ministry of Culture has developed a program to create synthetic images for architectural analysis from three- dimensional photogrammeteric datasets.

A complete documentation of an architectural object makes it possible to reconstruct the whole object both geometrically and pictorially. In the past the geometric documentation was performed using line maps, e.g. from photogrammetric restitution, while the pictorial aspect was mainly covered by conventional photographs. Today digital photogrammetry and digital surface description techniques allow for the combination of the geometric and the pictorial aspect in a complete documentation of an architectural object. This paper presents some experiences with visualization of architectural objects. At first, various ways of digital surface modelling are described. Then possibilities of visualizing digital surface models (DSMs) are shown in practical examples. The paper is concluded with some recommendations.

The Working Group V/3 of the International Society for Photogrammetry and Remote Sensing (ISPRS) was founded in 1988 at the 16th ISPRS International Congress. Since that time it works on " Image Analysis and Image Synthesis in Close-Range Photogrammetry ". The following report deals with concepts and topics which should deeply be investigated during the second half of the research period.

Abstract. The study of the aspect graph of a three-dimensional object has recently become an active area of research in computer vision. The aspect graph provides a complete enumeration of all the possible distinct views of an object, under a particular model for the viewpoint space and a particular definition for "distinct." This paper gives a tutorial introduction to the aspect graph, surveys the current state of the art in algorithms for automati- cally constructing the aspect graph, and describes some possible applications of aspect graphs in computer vision and computer graphics.

This paper presents parts of a research project designed to meet the need of automated or semi-automated object measuring and description in digital images. Different sources of information are used to provide the necessary information to generate different hypothesis regarding the object. Information can be provided by feature extraction, logical knowledge of the object, a CAD-model or similar. The main objective of the system is not in the field of object recognition but rather object description. The searched objct is prescribed as a generic model. To be able to compare hypothesis of models of different complexity other measures than maximum likelihood estimates have to be calculated. The method of Minimum Description Length is investigated for this purpose.

This paper describes the use of Disparity Space for automatic stereomatching, differential rectification and DEM production. Any matching technique which produces local (potentially ambiguous) matches can be incorporated within the Disparity Space system. A fast, optimal solution is obtained using Dynamic Programming. We have combined image intensity, local edge magnitude, local edge orientation and the output from a Laplacian of Gaussian to obtain very dense range maps. Experimental results with close range images are reported. The method has been implemented on a UNIX Workstation and is highly suitable for implementation with parallel processors.

The regularization method, which is performed by minimizing an energy functional of the image, has recently been applied to many ill-posed problems in computer vision. Notably, Grimson(1983) developed a regularization method for surface reconstruction which used a sparse set of known elevation data. We have developed an approach to surface reconstruction using both contour image data and a sparse set of known elevation values. We define a new energy functional which integrates three kinds of constraints : smoothness, fitness, and contour line constraint. These constraints seek to ensure that the reconstructed surface smoothly approximates the known elevation values and has the same height value for all points on a contour line. The energy functional can be minimized by solving a large linear system of simultaneous equations. We have successfully reconstructed a detailed 3D topography by applying this method to contour lines and known sparse elevation data extracted from moire images and topographic maps.

The physical properties of photographic roll film in conjunction with the design of small format cameras are generally optimised for ease of use and reliability during pictorial photography. Such design contributes greatly to the problems associated with the accuracy of calibration and analytical data reduction of non and semi metric small format imagery. The results of experimentation into both in-plane and out-of-plane film deformation, using a variety of commercially available 120, 220 and 70mm monochrome film stocks, are presented. Physical parameters investigated include environmental conditions, image density, processing regime, measurement and film back variations. Some results from the close range calibration of a modified small format camera are discussed in the light of the above experiments. A practical analytical data refinement system is envisaged, allowing potential accuracy to be balanced against the economics of the time consuming measurements of reseau images in an analytical stereoplotter.

For the attainment of the highest accuracies in close-range industrial photogrammetry it is necessary to account for the variation of radial distortion within the photographic field, especially for large-format lenses. In this paper an empirical correction model is introduced which overcomes serious shortcomings in the traditionally applied geometric correction approach. The new model has been tested with success on a number of medium- and wide-angle, large-format lenses. The results of sample tests are presented, and the effectiveness and practicability of the empirical approach are discussed.

This paper presents the new, microprocessor controlled, large format film camera Rol lei LFC metric. By means of rigorous reseau technique this camera defines the image space with high geometric accuracy and reliability. The camera is designed to meet the de- imands of close-range industrial photogrammetry.

This paper introduces the Linhof METRIKA as a new 4" x 5" roll film camera for close-range photogram- metry. It was aimed to develop a robust, precise and moderately priced camera which is rather handy and light- weight despite of the 4" x 5" photo format. Lens cones of 90 mm (wide angle) and 150 mm are available equipped with focussing stops which reproducibly fix a set of interior orientation parameters. Film flattening is provided by both a vacuum system and reseau technique. The design of the camera allows the interchange of reseau plates with different reseau arrangements. All operating functions of the camera are electronically controlled. First results of test field calibrations are presented which certify the high accuracy and physical stability of the camera. In addition, examples of applications of the METRIKA to architectural and industrial photogrammetry are given.

In this paper, we propose a new method for extracting vanishing points from real scenes, which exhibits linear computational complexity and good precision. This technique is very useful for camera calibration in photogramme- try, for the recovery of the motion of rigid objects and for the reconstruction of 3D scenes. The linear computational complexity is due to the introduction of the polar space, which permits the selection of the segments that converge on the same vanishing point, before computing the vanishing point itself. Extensive experimentation on real images shows that vanishing points can be identified and located even in cluttered images.

This paper considers the segmentation of range image measurements into surface patches which are either plane or curved and which are described formally by a function. After a formal description of the segmentation, we present and compare three methods suited for plane and curved patch segmentation and show the results of experiments conducted for testing their practical behaviour. The two first methods use the classical approach of region growing whereas the third method is based on a relaxation process. This original and last method exhibits simplicity and low computational complexity. Thanks to its parallel nature, it can be considered as a good candidate for range image segmentation in real-time applications.

The automatic processing of stereo images for 3D information extraction can be simplified by colour classification of the stereo image pairs prior to the correlation matching procedures. The number of corresponding pixels to be matched is drastically reduced, if only those pixels on the epipolar line are correlated which belong to the same class of colours. Colour classes of natural scenes like aerial photographies are usually composed of complicatedly shaped clusters which makes the manual setting of RGB classifier parameters an almost impossible task. We present a real-time IHS-colour classification system which uses neural network principles based on self-organizing look-up-tables for learning typical colour classes . A learning rule for the supervised training of this LUT classifier is presented . The proposed LUT classifier shows all the positive features of a 3-layer perceptron Neural Network, but performs 70.000 times faster then a simulated perceptron network and uses low-cost, commercially avai- lable components. The height measurement of plantlets for the automation in greenhouses is presented as a typical application of these principles.

A new texture feature, called Direction Measure(DM), is proposed in this paper, The new feature is based on the principle that in a homogeneous texture the gray values of pixels along any direction must change according to certain regularity( determined or stochastic); To determine such kind of regularity can get much information on the texture structure or statistical properties. The DM can also be easily extended to rotation-invariant features which can recognize the same texture no matter in what orientation it is pictured. The new rotation- invariant features are also very effective and are really rotation-invariant. Another advantage of the DM lies in that it can be easily computed and implemented by multiprocessors in a parallel way.

Softcopy photogrammetry's advent is a product of current advances in computer workstation technology and the low cost of image processing boards. Photogrammetric high resolution sensing remains, however, the realm of classical film-based photography. For softcopy-based digital photogrammetry to succeed creative solutions are needed to convert film to pixel arrays. We describe a novel scanning concept that permits one to convert a full frame of metric photography into an array of 32,000 x 32,000 pixels, or it permits the interactive "grabbing" of windows of pixels with sub-pixel accuracy while supporting a software-controlled zoom range with minimum pixels of 811.m and maximum pixels of 170p.m. At the heart of the new concept is the so-called "invisible reseau". Implementation of this new concept is in the form of the VX-series of scanners. The concept is discussed, and performance characteristics of the VX-Scanner are subject to analysis. The issue of "optimal" scanning parameters in both geometry and radiometry is a concern. The benefits derived from an interactive zoom-based approach to scanning are being highlighted.

A computer program package has been developed which combines photogrammetric numerical calculations with a graphical 3D-editor for the measurement of close range photographs. Data acquisition will be provided by scanning the images. Based on digital images, the editing of point and line information is done at the screen. The graphical editor is supported by means of bundle adjustment techniques. The developed program package will be explained and demonstrated by an example.

For the description of deformations and dummy motions during the crash, the Volkswagen AG uses 16mm high-speed drum cameras with frequencies of 400 pictures/sec. A system for a digital photogrammetric evaluation of the 16mm images has been developed. Several images of one epoch are completely digi- tized by a VIDEK Megaplus CCD-camera. After the measurement of signaled points in the digital images and a first orientation of the pictures using a graphic display, object coordinates are to be computed by a bundle adjustment. The interior orientation of the different cameras are deter- mined by simultaneous calibration. First experiences with the handling of the system, which in principle is useful for the photogrammetric evaluation of any digital images, and the precision of the point determination will be presented.

One of Kern's industrial measurement systems, SPACE, uses motorized theodolites equipped with CCD cameras in the telescope. This paper outlines practical mathmatical models, currently under evaluation, for relating image coordinates to angular pointings. The objective is a calibration method for video-theodolites which generates corrected pointings for targets imaged off-axis.

The calibration of comparators (or analytical plotters or digitizers) very often is achieved by means of a reseau of points on glass or film (grid plate) situated in contact with the measuring field of the comparator. From two sets of information the calibration data normally are deter- mined: from the comparator measurements of the reseau points and from their given control data. The procurement of high precision control data is costly. We, therefore, have developed the so far used procedure into one with only very few control data or even without any control data (= free selfcalibration). By choice of the size of the reseau and the density of marks the degree of calibration may be properly fixed. The new procedures have been successfully tested at the analytical plotter WILD AC 1 with results of high accuracy.

The increasing use of CAx techniques in the production processes and the continuously increasing pressure for quality assurance through regulated processes require a more extensive integration of measuring techniques in the manufacturing and data flow than in the past. For this reason, around 1985 the first considerations were developed in the quality assurance of the Volkswagen Organisation for a general data concept for use of coordinate measurement techniques (contact and noncontact) in CAI. The basis of all strategies was and still is a programming system for the generation of measuring programs, that are independent, i.e. excluding component specific, of the method of measurement (system AUDIMESS), as integral parts of the general system VWGEO.

The dimensional control of Agip's offshore structures by means of photogrammetry is foreseen during the structure's construction or at the prefabrication yard. The purpose of this check is to ascertain whether the parts have been built in correspondence to the design's dimensions. It can be achieved through the calculation of diameters, center distances, angles. The photogrammetric process determines the coordinates of a certain number of points readable on the surface of the structural component. Agip's control procedure involves, first of all, processing of these coordinates by means of software program in order to determine the mean radius and the pipe axes directions. Afterwards the coordinates are again processed, this time by means of the Cad system, where the "as built" model will be compared with the theoretical model, previously filed during the design processing. The comparison between the two models allows the detection of any discrepancies and their possible correction.

The objective of this paper is to present a theoretical model which will create a computer vision system capable of monitoring the fabrication of a facil- ity. The monitoring process would be able to identify out-of-position components and to re-create an as-built CAD model from the construction process. An as-built schedule would be a direct output and would provide for improved scheduling inter action and analysis. While computer vision .technology has not reached maturity where arbitrarily complex scenes can be processed and "understood", there h reason to believe that a vision system for monitoring the fabrication of a facility can be developed. To create such a vision system will require a number of tasks. The focus of this project is to use the information in the CAD system together with the camera model, the camera location, the orientation of the opti- cal axis and the positions of the illuminators to predict how the objects in the facility should appear. This information can then be used in "top-down" analysis of the scene. In a top-down analysis a scene model is used to guide the search for the objects in the scene. While developing sophisticated computer vision systems has, in general, been difficult, developing sophisticated top-down vision systems has not.

Dental medicine needs to observe the motion of the jaw with respect to the skull in three dimensions. This represents, therefore, a problem domain in which one has to observe, in real-time, the motion of one three- dimensional body in 3-D space (the jaw) with respect to another three-dimensional body in 3-D space (the skull) which both may move independently. This paper discusses an innovative solution to this requirement. The solution is implemented on a personal computer and is based on light-emitting diodes that are attached to the two moving 3-D objects. The innovation has been granted patent protection2. An element of the solution is the hand-held 3-D cursor whose position is also trackable as a separate three-dimensional body in 3-D space and allows the user to identify the XYZ coordinates of any point by a free-hand pointing action. Applications of this real-time 3-D measurement system are not only in dental medicine but may extend to mechanical engineering, medical gait analysis and other applications where 3-D motions need to be tracked in real time.

During the design/development of the Canadarm Remote Manipulator System (RMS) in the 1970's for the NASA Space Shuttle, the NRCC, National Aeronautical Establishment, Structures and Materials Laboratory initiated the development of an Online 30 Hz Video Real-Time Photogrammetry System (RPS) for Real-Time 3-Dimensional Control. With the initiation of the Canadian Astronaut Program and Canada's participation in the Space Station, a protoflight Space Vision System, based on the RPS technology, was designed and built for integration with the Shuttle Closed-Circuit Television System (CCTV). The SVS accepts one or two CCTV selected camera inputs and provides, as output, a real-time display of the photogrammetrically derived 6-degree of freedom guidance information to the RMS operator in symbolic and alphanumeric form. The SVS makes it possible, for the first time, to carry out a series of Shuttle-Manipulation tasks in the weightless/thermal/lighting environment of space using real-time guidance information. This paper describes the basic multi- processor architecture of the SVS, the photogrammetric algorithm(s) defined multiple target array payload and targeted berthing hardware, the pre-flight camera calibration set-up procedures, and the on-orbit reference calibration procedures for task related coordinate transformations to cater for thermally changing shuttle-RMS deformations. The series of experiments and graphic displays, supported by the task configuration database software of the SVS, will be summarized.

Using stereo vision and marks pasted on wall to solve the guidance and the environment learning problem for a mobile robot is proposed. A circular window is used to detect corner points as features in the scene. From the perspective transformation matrices of the two cameras and matching point-pairs in images the 3-D coordinates can be determined. With ground projections of these space points and the constraint of minimum diameter of the mobile robot, a few separated polygons are used to represent the occupied space of the surrounding obstacles. With the corner points of the mark the location of the mobile robot can be determined not only by the stereo vision system but also by each of the two cameras with plane-motion constraint. Experimental results show that the depth measurement error is less than 2%, the location determination of the mobile robot working on the ground plane is less than 5%, and the map of the occupied space can be used in further path-planning or collision avoidance.

For many tasks in turbulent flow research the simultaneous determination of tracer particle coordinates with high spatial and temporal density is required as a basis for particle tracking velocimetry (PTV). As a simultaneous, non-contact and automation-friendly method digital photogrammetry is a suitable tool to provide this information on-line. This paper describes the implementation of a system based on three CCD-cameras, which can determine the coordinates of up to 900 particles per image triplet. After an overview about the hardware used for acquisition and storage of three synchronous sequences with some hundred images each, the chain of algorithms for a completely automatic processing of the sequences is shown. These algorithms deal with some special problems arising from the task, for example the multimedia geometry, the high particle density which leads to overlapping particles in the images, and the fact that there is no continuous surface in object space, which causes ambiguities in matching. It will be shown, that these ambiguities can only be solved reliably by a system with at least three cameras.

At the Federal Institute of Technology at Zurich, an interdisciplinary research team in collaboration with the industry have developed a robot-theodolite. Such future instruments have not to be operated. They detect the target points automatically by themselves, calculate their coordinates in whatever geodetic system and telecommunicate the results to whatever spot in the field and/or a dataprocessing centre. This paper deals with the techniques of such instruments, with possible applications and with metamorphic influences on the surveyors' profession.

A submarine consists of cylindrical, spherical and conical sections, which are joined together in the construction phase. It has to be checked by measurements whether the sections have been constructed with the required precision. In order to proof to a ship- building company in the Netherlands that traditional measuring methods for quality control can be replaced by photogrammetry a test measurement has been carried out. For this test a conical submarine section has been measured twice. The first time in the traditional way and the second time by using photogrammetry. In the photogrammetric procedure retrotargets, an analytical plotter and a bundle adjustment program have been used. In this paper different measuring methods for quality control will be described shortly. The advantages and disadvantages of each method will be discussed. It will be shown in which way the required object coordinate precision of 1 mm or smaller could be obtained by photogrammetry. It is shown that curvature deviations determined with photogrammetry are almost similar with the deviations as obtained by using the traditional measuring method of the ship-building company.

The W. M. Keck Observatory will house the largest optical telescope ever constructed. A multi-segmented, 10 m diameter mirror will allow the telescope to look into space over a distance four times further than any other current system. The support cell for the mirror segments was manufactured in Spain, partially dismantled for shipment and then re-assembled and installed on the mountain of Mauna Kea in Hawaii. Photogramme.tric surveys of the structure were made both in Spain and Hawaii. Measurements in Spain served as acceptance criteria for the structure in addition to detailing as-built conditions. Loaded deformation was also tested in Spain to confirm conformance to design. The measurements in Hawaii checked for effects of shipment and also proper installation in a very different physical environment. All surveys yielded similar precision of 0.03mm RMS one sigma (1 part in 300,000 of the object diameter). This paper describes the major phases of the project, details specific design and operational characteristics of the surveys and presents the results obtained.

Stereoscopic observations of 70 mm colour transparencies have been used in bundle adjustments to determine deformations of structural walls subjected to mine subsid- ence and the Newcastle, Australia, earthquake of magnitude 5.5 on the 28th December 1989. The photography was taken with a pair of Hasselblad 500 ELX cameras which had been modified by the addition of a glass reseau plate. The cameras were fixed 2 m apart on a bar, with camera-to-object distances varying from 10 m for the mine subsi- dence tasks to 30 m for some of the earthquake analyses. The stereoscopic observ- ations were made on an Adam Technology MPS-2 Analytical Stereoplotter with only the plate co-ordinates used in the bundle adjustment. Closures of under 4 micrometres on the frames were obtained from the bundle adjustments with an extremely low rejection rate of observations being a notable feature. The unusual combination of stereo- scopic observations, an analytical stereoplotter, non-metric cameras, bundle adjust- ments and a CAD program to provide timely results, is discussed.

The optimum determination of the position of projective centres in industrial photogrammetry can be solved twofold: On the one hand simulations can contribute considerably to solve the problem, and on the other hand analytic formulations might be used. For reasons of powerful network design the latter ones are preferred because here different objective functions can be integrated in one solution strategy only. The paper reviews the state-of-the-art in analytic first order design. It introduces criterion matrices for the coordinates, which are the 'observations' for solving the design matrices. The algorithm used during optimization is the Lemke algorithm. That means, the optimization is performed by quadratic programming being in correspondence with linear complementarity problems. Besides the objective functions for coordinates further boundary conditions have to be considered such as constraints in accuracy, position and costs.

Recent developments of video cameras and frame grabber technology have led photogrammetrists into the fields of digital image processing and machine vision. This paper describes the components of a digital photogrammetric system for close range applications. The approach to image matching involves the location of preliminary matched details based on features which are used as initial approximations to determination of precisely matched areas on the two images. Image matching based on grey scale values uses the least squares matching method. A software package has been developed to determine object geometry from overlapping digital images, and results from test are presented for three combinations of base/height ratio. Future developments will be based on the use of a knowledge base to control the searching for matched points.

A system is presented that allows maps compilation in a fully digital way: digital image and D.T.M. are used in order to obtain an orthoimage; it will be the base for numerical and graphical map compilation. System concepts are discussed and some applications presented.

There is increasing use of electronic sensors and digital signal processing for measurements of optically acquired data. Applications include automatic inspection, surveying, remote sensing and photogrammetry. Sensors, at the present time, require subpixel methods to improve the resolution above that available given the spacing of sensing elements and the analogue to digital conversion resolution. This paper reviews proposed subpixel methods in the context of an increasingly important application, namely, the determination of the position of a laser spot on a sensing array for triangulation. A number of techniques are chosen and analysed experimentally. Their performances are compared and contrasted with respect to spatial resolution, quantisation accuracy and noise. For the comparison, use is made of simulated data, and real data obtained from a triangulation system9.

A new approach to reconstruct the three-dimensional surface of the object space from digital images is described. All the object points obtained by an automatic orientation procedure lead to a first approximation of the surface. Edges are computed for one image and matched to the other image by grey level correlation or least-squares matching through the scale space. To every discrete step in the scale space there exists the digital stereopair (image pyramid), the corresponding surface (digital elevation model DEM) and the warped images. The warped images in this discrete scale space representation correspond to digital orthophotos obtained from the DEMs that result from matching the image pyramid. We propose to use the warped images on every successive level in the image pyramid in order to reduce the foreshortening problems associated with any area-based matching method. The paper describes the method and some experimental results are reported.

FAST Vision approach C. facets stereo vision) for object surface reconstruction comprises the simultaneous least-squares computation of object surface and object optical density D X,Y) from image grey values. Both functions are represented by finite elements in facets. In this paper investigation on the size ratio of pixels and facets for the optical density function D (X,Y) are presented using two different representations: the bilinear and the bicubic finite element representation. For both a ratio of 2x2 pixels per D-facet comes up to be a reasonable compromise between good approximation and good regularization.

New applications continue to emerge for machine vision and real-time photogrammetry, particularly in industrial inspection and biomedicine. Solutions to automation and practical problems are the key to the success of this relatively new technology. Calibration, illumination, edge definition and integration with a priori known information are addressed.

A system for real-time applications in close-range and industrial photogrammetry is presented. Special attention is given to system design and implementation. The system consists of a variable number of active and passive image sensors controlled by an multi-processor computer environment. The image processing unit incorporates various methods for automated measurement of targets, laser spots and object elements. System calibration is done by rigorous bundle adjustment. Target determination is performed by single-image measurements, while spatial object elements (circles, planes, edges) are processed by multi-image edge-matching techniques. Overall system control is implemented by a flexible programming language. The system can work in two different modes, teach-in and automatic measurement. Both hardware and software components are designed for use in an industrial environment. Particular importance is given to ease-of-use and robust operations. The system will initially be used for quality control applications in the automobile industry.

It has been shown earlier that efficient active triangulation methods for range data acquisition can be devised by employing an appropriate time-space encoding. In this paper we show that the necessary computational burden to compute range values by means of these techniques can be reduced drastically by introducing weak geometrical constraints for the projector camera configurations. Furthermore, we suggest the concept of a virtual measurement coordinate system reducing the triangulation to simple one-dimensional LUT operations. Thus, the range acquisition technique can be implemented very fast in a low cost PC based image processing environment. We show how to calibrate the system and give some experimental results.

A prototype of a system to measure and represent small objects is presented. It consists of two CCD cameras, a motorised rotation plate and a projector, all controlled by a microcomputer. The measurement of objects is performed by automatic determination of heights along curves. Each curve is obtained by localising a point projected on the object which is rotated around itself. The rigorous camera calibration assures a precision of the measured coordinates of the order of 0.5 pixel in object scale. After completion of the digitisation, software for digital cartography is used to represent the object and to determine further quantities such as distances, surfaces and diameters. An example showing the use of the system is given.

Some special tools for car manufacturing and some parts for cars are requiring geometrical accuracies within few microns. Up to now the check for acceptance will be done by mechanical 3-D-measuring devices. This is very time consuming and expensive. Based on off-line tests with macro photographs and evaluation by close range photogrammetry, an on-line solution with CCD-cameras is under development. The necessary accuracy of some microns in the object space will be reached over distances up to 800 mm by orientation of the cameras in relation to a precise control field which is presented by a large reseau grid.

We have proposed a method of stereovision applied to urban areas, which consists in using surface models in stereovision [8]. Using surface models is possible, not only to correct disparity errors and thus get a more accurate stereorestitution, but also to reconstruct a complete scene. In this paper we describe experimental tests of the method comparing the corrected and fit stereo output of our method with an accurate DEM obtained by an analytical plotter. We show that an average of 0.2 pixel precision of disparity can be achieved on a real complex scene by our method. Potential error sources are also discussed.

Measured changes in vegetation indicate the dynamics of ecological processes and can identify the impacts from disturbance. Traditional methods of vegetation analysis tend to be slow because they are labor intensive; as a result, these methods are often confined to small local area measurements. Scientists need new algorithms and instruments that will allow them to efficiently study environmental dynamics across a range of different spatial scales. Presented is a new methodology that addresses this problem. This methodology includes the acquisition, processing and presentation of near ground level (NGL) image data and its corresponding spatial characteristics. The systematic approach taken encom- passes a feature extraction process, a supervised and unsupervised classification process, and a region labeling process yielding spatial information.

The article presents the principal aspects of noise and object elimination from automatic correlation data by applying an algorithm based on the finite element theory. The algorithm developed is based on the establishment of a 3-D surface of finite elements fitted to the coordinates from the automatic correlation data by means of a least square adjustment. Three different approximations are discussed for noise and object elimination: a classical elimination by thresholding the residual errors; elimination by applying the Baarda error detection theory and a deterministic elimination using vectorized contours from an image processing.

The digital production of orthophotos must not be restricted to research laboratories but can be part of the daily work in a land surveying office. An image processing system is presented which combines the facilities for fast computation and handling of ultrahigh resolution images with an application specific user interface.

Abstract In this paper a parallel computer architecture for real time image processing is described. The architecture centers on the direct mapping of a synchronous dataflow graph on hardware and software. Each node (or group of nodes) is replaced by a hardware or software module. The processing elements are interconnected by a flexible and fast communication network based on multiple interruptable buses. The prototype SYDAMA I (SYnchronous DAtaflow MAchine) has been built. On this system, many low level image processing algorithms run in real time at video rate. Applications of the system are real time computer vision, real time image enhancement, real time color seg- mentation, real time depth data processing, robotics, and autonomous vehicle guidance.

Recognizing specific patterns plays an important role in digital photogrammetry. A common task is locating special targets in an image, such as control points. The paper explores the applicability of Parallel Associative Memory (PAM) for searching targets in aerial photographs. The PAM we used in our research is based on the Nearest-Neighbor algorithm and uses the Hamming distance as a measure of closeness to discriminate patterns. This approach is particularly successful if the patterns can be described logically. Our research focused on targets typically used for ground control points. We tried to develop a method which parallel to the data acquisition process sorts out the approximate target positions where the precise localizations are needed. A library with different targets was entered into the PAM. Image patches that were moved across the image were constantly compared with the library by determining the Hamming distance. The results are encouraging. The majority of control points in different images were correctly identified and only a few targets were wrongly matched.

An automated modeling system that represents an object body by a solid model of polyhedral approximation was developed using multi-directional image inputs. The principle of this solid model generation is based on the calculation of viewing pyramids consisting of the image boundary and the corresponding focal point. Applications to the non-contacting three-dimensional measurement of the shape of irregular and complicated object such as a doll, a fish, a spiral shell, and a lemon, to the automated mesh generation for the boundary element analysis of the lemon, to the CAD of a tillage blade, and to the shape, deformation and motion analysis of an aerodynamic tuft, a small tracer particle, and an alcohol wick flame for the flow visualization are presented. It appears to have considerable utility in bio-mechanics and various industrial applications.

Some principles of using template images for close-range photogram- metric coordinate determination are described. The primary use is the automatic stability control of the photogrammetric stations. In the case of applications, such as within manufacturing process cont- rol, the template images substitute the need of manual targetting.

Traditionally, diseases of the knee joint are evaluated by grading radiographs, i.e. x-rays are visually inspected and assessed for joint narrowing, spurs, lesions and. sclerosis. Our concept for the quantification of bone changes in diseased knee joints is based on slice-wise measured volumetric CT-data (Computed Tomography). 61 slices, with an interslice distance of one millimeter, are measured with a high resolution low dose CT-system. Considering its three-dimensional context, each slice is separated into objects (femur, patella, tibia, fibula). The contour sets are then used as input for an automatic triangulation procedure. Finally, the surface of the objects and the underlying bone structure is analyzed with regard to localize density loss, lesions, surface roughness, width of joint gap, and so on. It is expected, that the quantitative parameters extracted from 3D CT-data will help to understand the gradual development of joint diseases and help to evaluate new therapeutic procedures.

A current major interest in orthopaedics is the improvement in the longevity and reliability of artificial hip joints, whose ultimate life is usually limited by failure of the implant/bone interface and sinkage of the implant. Measurement of movement at this interface during the first two years on an implant's life is expected to correlate closely with the overall life-span of a total joint replacement, but these movements are too small to be measured by conventional, uni-planar radiography. Other workers have demonstrated the value of X-ray stereo photogrammetry for this application and have shown that the mathematics of analytical reconstruction is simplified by the absence of many distortions normally present in conventional photogrammetry. However, X-ray photogrammetry of the human hip under normal load presents some particular practical problems including degradation of the X-ray image due to the large size of the object, support of the infirm patient, landmark identification on the bone and implanted components, and ease of film measurement. We report here on the performance of a number of novel approaches to these problems intended to reduce X-ray stereo photogrammetry to a manageable clinical research technique. These have been implemented at the Nuffield Orthopaedic Centre for application to substantial numbers of patients in clinical trials.

A real-time program for the processing of scanning electron microscope images has been completed on Wild BC2 analytical plotter.An orientation method based on parallel projetion will be introduced. Contour, perspective maps. Digital Surface Model (DSM) and a lot of derived information can be obtained by means of this software. An actual application is shown at the end.

The goal of our work is to noninvasively assess the abnormal contraction pattern of the heart in patients with hypertrophic obstructive cardiomyopathy, by means of Magnetic Resonance Imaging (MRI). To study the motion of the heart wall, the imaging plane is labelled a few milliseconds after the RÃ¢â‚¬â€wave with a grid pattern using the technique of Spatial Modulation of Magnetization (SPAMM). During systole several ECGÃ¢â‚¬â€triggered short and long axis views of the heart muscle are acquired with a conventional Fast Field Echo sequence. In a preliminary study of the normal left ventricle a clockwise twist of approximately 10 degrees at the base is found, increasing towards the apex, whereas patients with hypertrophic cardiomyopathy show a complex motion pattern, with a clockwise twist in the basal and counterclockwise twist in the apical segments.

Conventional cellular and histological analyses are generally based on planar images. New preparation techniques in the field of immunohistochemistry and in situ hybridization demand a more sophisticated analytical approach. Our method to detect irregularities in the number of chromosomes present in interphase nuclei of normal and neoplastic cells and to characterize aberrations in the structure of these chromosomes makes use of a combination of confocal laser scanning microscopy (CLSM) and 3-D imaging. In this paper we describe a computer-assisted setup designed to localize in situ hybridized chromosome 1 of human sperm cells. In order to synthesize a 3-D image of the structures of interest, the stack of slice images generated by the CLSM is processed appropriately with the aid of a parallel distributed computer architecture based on transputers. The resulting images or particular aspects thereof are visualized on a high resolution display and related to new information in reproductive biology.

This paper presents an algorithm for straight edge extraction from intensity images and an algorithm for straight line matching. In the first part of the paper, straight edge extraction is described. Image data are first processed by the operation of edge support focusing to remove unnecessary image details. An edge support is formed in this process. Then, straight edges are extracted from line support regions, which are segmented from the edge support. In second part of this paper, we describe straight line matching using a matching function, which characterizes the similarity of edge lines of two images and is based on not only the geometrical relations of the lines but also the information from the intensity images. A technique of kernel matching is applied to reduce the cost of computation. The motivation behind this paper is our work on motion estimation from line correspondences of sequential images where straight edge extraction and matching is an essential first step. The output data of the algorithm can also be used for calibration of stereo camera setups. The results of experiments using indoor and outdoor scene images are shown.

An automatic procedure for tracking signalised points on multiple, differently moving surfaces will be described. The practical tests involve tracking of points on a person walking within a calibration frame. Three simultaneously acquiring CCD cameras, which are oriented using control points, provide the input data. For implementation, the hardware (H/W) and software (S/W) of a digital photogrammetric system have been used. The procedure includes extraction of the signalised points and finding corresponding points in all three images, thus providing 2-D and 3-D coordinates and tracking using the information in both image and object space. Reliability aspects such as occlusions, multiple solutions and different backgrounds will be analysed. The effect of a third image on reliability will be analysed.

The selection for control points is a necessity in registration for remotely sensed images. This paper is to propose a new progressive method to automatically generate control point pairs with uniform distribution. The Voronoi-Delaunay dual graph is used to predict the optimal locations first. Interest operators are then used to extract point features for potential control points. Finally, a hierarchical coarse-to-fine matching procedure is applied. The area-based matching is also integrated for accomplishing the image correspondence to sub- pixel level. A consistency check by Robust Estimation is also included. A pair of digitized aerial photos are used in the case study. Results indicate that the proposed has many attractive merits.

Abstract An algorithm based on the Hypothesize-and-Verify paradigm is presented to register two stereo frames taken while a mobile robot navigates in an indoor environment. The rigidity assumption plays an essential role in the algorithm. The rigidity constraints we formulated are complete for 3D line segments, which allow to compute a unique and rigid motion from two pairings of segments if they satisfying those rigidity constraints. Two appli- cations are presented in this paper: model-based object recognition, multiple object motions.

This paper presents a procedure for automatically fine-tuning the control parameters of a noise-tolerant matching algorithm. The construction of correspondence relations between 2D models and image representations will be executed by computing morphisms between relational structures. Tolerance parameters for model attributes can be modified in order to apply the matching algorithm to real world images. Evaluation functions are incorporated for measuring the quality of the correspon- dence relations. An adaptation procedure automatically modifies the tolerance parameters to reach acceptable corresponden- ce relations. For initializing the adaptation procedure the user only has to specify initial values of a minimum set of tolerance parameters. Geometrical dependencies between attributes of model components are employed for determining initial values for the rest of the tolerance parameters. Additionally, the user has to define several criteria for accepting correspondence relations. These acceptance criteria will be specified by fixing thresholds for the evaluated correspondence relations. Several modification strategies are included for reacting appropriately on the outcome of the evaluation functions. The system will be demonstrated in the practical application area of inspecting classes of Integrated Circuits to detect manufacturing errors.

When a camera is to be used to guide a robot to pick some object, one of the first thing to do is to cali- brate the camera. This consists of establishing the correspondence between the three dimensional (3D) world coordinate system and the two dimensional (2D) camera coordinate system. The correspondence is given by various camera parameters which comprise the interior orientation (focal distance, radial distorsion and aspect ratio) and the exterior orientation (rotation and translation of the camera). This problem is also known as the "interior/exterior orientation problem" or the "hand-eye calibration problem". In the present paper, the calibration problem is formulated as the problem of finding the best parameters that fit the observations of known test points. Then, a new numerical procedure is described to obtain the best parameters in the least square sense. The main result of the present paper is that the errors corresponding to each test point can be approximated by two linear equations in terms of the independent camera parameters. Then, these linear equations are combined to produce a least square matrix equation in term of the independent camera parameters. This numerical method uses only several . systems of linear equations of small size. The method presented is simple which makes it adaptable to other camera calibration problems such as stereo camera calibration for direct 3D measurements.

Some techniques for laboratory calibration and characterization of video cameras used with frame grabber boards are presented. A laser-illuminated displaced reticle technique (with camera lens removed) is used to determine the camera/grabber effective horizontal and vertical pixel spacing as well as the angle of non-perpendicularity of the axes. The principal point of autocollimation and point of symmetry are found by illuminating the camera with an unexpanded laser beam, either aligned with the sensor or lens. Lens distortion and the principal distance are determined from images of a calibration plate suitably aligned with the camera. Calibration and characterization results for several video cameras are presented. Differences between these laboratory techniques and test range and plumb line calibration are noted.

Aiming to accelerate the work at archaeological excavation sites, a photogrammetric method using video cameras and a digital comparator is proposed. Thanks to the elimination of the need to develop films and to use heavy photogrammetric plotters, the work can be executed at the excavation site. The image acquisition and processing system is presented together with results of a simulation of an excavation.

A multi-discipline comprehensive archaeological study is being carried out to the well-known Chinese Emperor Qin Shi Huang's Mausoleum. In this paper, the research de- velopment and application of photogrammetry and remote sensing techniques will be des- cribed. In the project, the data and images were acquired by using the techniques of close-range photography,low-altitude photography and aerial remote sensing ( black-and-white and color infrared photography, thermal in frared scanning ). Several large scale present maps and orthophoto maps have been made as well as elevation drawings of different kinds of typical terra-cotta warriors, horses and weapons. In the area of known historical monuments, the inter pretation of remote sensing imagery made the de- tection be accurate upto 85%, while in the unknown area, it helped to make new archaeo- logical finds and to determine the range of flowing slopes. The operation procedures and methods for application of remote sensing technique in field archaeological work are stu- died and investigated.

The documentation and mapping of small archaeological pieces was done by photogrammetric me- thods using a small format camera equipment and a transportable object-space control set. During a two years research project it was possible to include 1500 fragments of ancient roman pottery into the project. About 250 stereo-photographs have been taken in various austrian museums and were set up on an analytical plotter. The set up of the imagery was performed only by the direct linear transformation procedure for both photographs of each stereo model without relative or absolute ori- entation. The interest from the archaeological point of view was the precise mapping of the appliques. The drawings and the stereo photographs of the ceramics build the base of the project collection.

Within the scope of making photogrammetric plans of the northern border of the Jebel Marra at Darfur/Sudan an archaeological general map 1 : 50000 of the surroundings of the medieval ruins of Uri has been produced using SPOT imagery and aerial photos. Beside the simple localizing of archaeological objects from the remote sensing material statements on the typology of settlements and buildings and on the stratigraphy can be made. This leads to the possibility to give information about the historic evolution of that region. It shall be verified in a thesis by extending the area of work to the whole Jebel Marra.

The maxillo-facial or plastic surgeon needs knowledge about the average, i.e. the standard form or size or size-relation of the human face as a whole or of parts of it, not only of the lateral or frontal profile, and control on any changes with time. Stereophotogrammetry offers a means to uniquely define, measure and compare size and form of any visible part of the human face, but the living and mooving and changing object man causes difficulties for the photogrammetrist. He therefore applies different and special methods and tricks for special tasks. Two of these methods and their basic ideas are presented: 1.) A single camera method for stereomeasurements of precisely rotated objects, specially of the muscles of facial expression on fresh male head specimens in order to facilitate the planning of corrective interventions in plastic surgery, and to offer information on the required size and measurements of donor muscles. 2.) A stereo camera method enabling maxillo-facial surgeons to exactly determine changes of the facial surface coordinates by using convergent non metric cameras, analytical photogrammetry and the well ripened methods of digital surface (terrain) models.

Moire Method is used to study the modifications of back shape of patients, with Postural Disturbances. Those mOdifications are induced by exercises or postures of auto- -correction, like changing the position of feet, plantar support, tilting of pelvis, side-shifting or by introducing prismatic lens. From all patients with Postural Disturbances, we obtain a first Moire topogram in usual standing position. A second one is obtained after teaching the correction. This second Moire topogram confirm or deny the pretended effect of the correction teached.

This paper discusses a technique for cornea shape measurement. Unlike the conventional method of concentric ring projection (Placido discs), this method can be used on ulcerated or scarred corneas or on non reflective surfaces. The tear film is stained with orange fluorescein and an illuminated pattern is projected through a blue filter and an image is captured through a yellow barrier filter. The points on the left and right images are matched and the cornea surface is derived. Multiple forms such as contour maps, deviations from sphericity can also be derived from this surface. Components of a digital based system are being developed and are described here.

Typical photogrammetric mapping systems could well be called 2-1/2-dimensional since they collect data for presentation on two dimensional maps by treating elevation as an attribute. However, in close-range photogrammetric applications, there is often the need to collect and utilize truly three dimensional data. Because of this, a new system, FoTo-G has been developed for three dimensional photogrammetric mapping applications. It is a production oriented software system designed to work with the highly unconventional photogrammetric image configurations which- result when photographing 3D objects. This paper describes several innovative and novel concepts which have been utilized to overcome traditional limitations and avoid common pitfalls.

Gauging with Machire Vision has been around since the early days of applications of that technology. With steady improvements in solid state sensor technology and sub-pixel software algorithms, Machine Vision can now challenge and eff6:tively replace some of the more traditional contact/air gauges for both off-line and on-line applications. On-line gauging with Machine Vision offers perhaps the largest potential since it provides the advantages of a non-contact gauging process for 100 percent inspection and the flexibility and data manipulation capabilities of Machine Vision for true in-process control. This can mean a process is monitored more closely to prevent manufacture of "bad" parts as opposed to inspecting for bad .)arts only after manufacture. This paper will examine some of the fundamental issues of Machine Vision used as a non-contact gauge, with definitions of the terminologies commonly used. Special emphisis is placed on the optical issues for on-line gauging applications.

This paper analyzes the relationship between the orientations and the curvature of corre- sponding edges in a stereo image of a scene. Exact relations are given in case of planar scene surfaces, and it is shown that the shape of the disparity surface is determined by the orienta- tion and curvature attributes. For curved surfaces the invariants are derived for a restricted class of scene curves. Experiments with the orientation invariant are reported.

At first a survey of discussion refering to expert systems in the area of photogrammetry and cartography is given. Typical components of an expert system are introduced and two examples already realized for photogrammetric tasks are introduced. Further topics are: A concept for an integration of FAST Vision within an expert system is developed: Also the possibility of the connection of FAST Vision, a bundle block adjustment program and expert systems will be discussed.

These studies aim to evaluate respiratory muscle authors have developed a real time system for function in childhood by observing regional capturing dynamic pictures of the breathing cycle of motions of the body surface during breathing. The patients using a pair of video-cameras, a two stereophotogrammetric analysis of biological forms channel split screen vision controller and a video- in medicine has been usefully employed for many cassette recorder with digital storage and effects, all years. Generally the methods previously adopted mounted on a custom built hospital cot. The have involved the measurement of conventional images to be measured are selected by viewing the photographs in comparators. Although these split screen in dynamic stereoscopic mode and methods have proved successful, the procedures are selected images are captured on an IBM personal very time consuming and this severely restricts computer equipped with video frame grabbers. their application to physiologic studies. The images to be measured are selected by viewing the split screen in dynamic stereoscopic mode and selected images are captured on an IBM personal computer equipped with video fram grabbers.

The quality check of plugs in human teeth and the detection of marginal defects and abrasion effects during a specified time period has been improved by photogrammetric methods, using imagery from the scanning electron microscope (SEM) for a three dimensional measurement. Due to the small magnification of the micrographs, caused by the object size, the geometry of the scanning operation required the use of perspective formulas during the photogrammetric set up and data registration procedure. Unneglectable image distortions, effected by the small image scale, has been detected by the use of a calibration grid and the stereo models where extended by an additional third image to meliorate the quality of the photogrammetric measurement. The quality of data acquisition was proved by mapping the whole tooth surface. The relationship between the models of different epochs of one object was established by the detection of features on the tooth surface without artifical control points and the breakdown of a specified part of the plug during the time of observation is documented.

Human/biological motion analysis is traditionally addressed as a problem of tracking a set of (active/passive) markers appropriately attached to the body part under study. General, fundamentally three-dimensional movements cannot be studied in this way. After having studied for some time the different aspects of such a subtly complex research topic,1,2 we propose now an approach which is model- driven, in the sense that it is based on an Animated Humanoid and on the comparison between the actual images of the body and the synthetic images of the humanoid. Our system (that we dubbed Kinesis) organizes the computation into three main phases: (1) Image (sequence) acquisition and processing, (2) Humanoid animation, (3) Optimization. Images acquisition and processing is performed on a VDS Eidobrain video- workstation, which allows image sequences to be stored from three video inputs. The second module relies on a distributed model of motor control, which solves motor redundancy through the regularizing properties of muscle elasticity.3,4 The optimization module drives the humanoid animation in such a way to find the best fit between the original data and the humanoid. Kinesis requires two calibration: the photogrammetric calibration of the (at least three) cameras and calibration of the humanoid. Preliminary results are presented.

Motography, combined with stereophotogrammetry or image analysis, was applied for a study on body surface changes during breathing. Quiet respiration produced no observable alterations of the anterior aspect of persons standing upright, whereas forced ventilation elevated and expanded the chest cage. Although remarkable differences of the respiratory movements could be observed for the individual as well as between the persons, quiet respiration seems to depend mainly on diaphragmatic action. Cervical and intercostal muscles, which elevate and widen the chest cage, are involved in enhanced ventilation.

Hyperkinetic movements, a predominant feature of diseases of the motor system, were measured by using a TV camera system that recognises reflective markers on the body of the patients and reconstructs their 3-D trajectories. Kinematic analysis of the movements allows a global assessment of the hyperkinesias and quantitative classification of torticollis, chorea and athetosis. The value of biomechanical analysis based on kinematic measurement in establishing invariant paramenters of hyperkinesia are discussed.

The ultimate aim of this work is to produce a control system for two dimensional measuring machines which will be capable of automatically seeking and finding 'target' images on photogram- metric plates, giving accurate estimates of the co-ordinates of the centres of the target and some objec- tive measure of the uncertainty of these estimates. It is well known that the target locating process is labour intensive, generally requiring days of work for operators to identify several thousand targets contained in a photogrammetric plate. Even using sophisticated image processing techniques, the scanning system still suffers from slow operating speed, intensive programming requirements and not being capable of adapting to different types of target. In order to minimise these deficiencies, an artificial neural network approach has been employed to develop the automatic scanning system. This paper describes the progress made on this application of artificial neural networks.

A traffic flow control system is necessary for preventing accidents and lighting congestion in the motorization era. The system should be provided with the functions to measure the 2-dimensional movement of each vehicle on a comparably wide area. This paper describes a study on a new traffic flow measurement system by processing periodically acquired video images. The system can decide the size of each vehicle and measure its 2-dimensional movement.

3-D data of wave patterns generated by a ship or ship model in running water are used for the computation of the wave resistance. The results are suitable to optimize the ship design. A series of investigations was carried out to determine the wave heights photogrammetrically. The water surface around a test model in an open channel was photographed with four simultaneously released partial metric cameras. The visibility of the wave surface was improved by scattering small particles onto the water. Stereopairs were measured on an analytical plotter in order to obtain a 3-D point cluster. Digital object models and various follow-up products such as perspective representations, contour maps and profiles were derived with the DTM program system HIFI-88.

The concept of an optical coordinate measurement machine (CMM) shall be presented in this paper. An optical CMM consists of image recording devices, lighting, texture projection and image processing hard- and software. The hardware components and the image processing algorithms will be described briefly and examples of industrial and other applications will be presented.

Forensic analysis of photodigitized data often requires that various image processing techniques be applied to the raw data in order to make it suitable for such analysis. However, image processing can amplify errors in the photodigitizing process. Therefore, a high fidelity photodigitizer is required if error- free processing is to be applied to forensic analysis. The requirements for such a photodigitizer are enumerated and discussed.

In the course of developing flight navigation equipment (FNE) for the existing and advanced aircraft major importance in attached to flight research and testing, the main goal lying in determining the accuracy characteristics of the systems and devices making up PNE. A successful solution of such tasks depends on the choice of a reliable and effective method of evaluating accuracy characteris- tics. For the last 30 years the photogrammetric method (PG) has been considered one of the most reliable ways of evaluating system accuracy characteristics during flight testing. The paper contains a summary information about the use of the PG - method in aviation equipment flight testing. A variety of different ways are discussed with respect to the specific flight experiment conditions, their special features, advantages, drawbacks and accuracy characteris- tics. There are given results of the PG - method repeated use for evaluating the accuracy characteristics of various navigation sys- tems and sensors, based upon different physical principles. The ef- ficiency of using the PG - method in PNE flight testing is also shown.

A machine vision system is developed for measurement and comparison of biological shapes such as the mouse vertebrae. The system is flexible and able to work under varying illumination con- ditions. The rate of growth and shape change of the vertebrae are evaluated quantitatively by using a new pattern recognition technique. The image segmentation process is made difficult since these im- ages are plagued by poor contrast and dropouts. In this paper, a review of previous work is presented, along with how this problem can be viewed in the context of the computer vision area. The system consisting of a a video camera (Panasonic CCTV), digitizing unit with framestore, optics and a microcomputer measures the dimensions and compares the shapes of complex biological structures. The image processing system helps automating the measurement problem of such complex shapes and objectifies the measurement results. Reproducibility is an interesting feature of the developed system. An assessment of the measurement accuracy and time duration was undertaken. Different steps in the implementation of this solution are discussed and results are presented. Although our ultimate goal is automatic measurement of biological shape, attention will be restricted to a fast method for both parallel outlining of the vertebrae and feature extraction. Experimen- tal results on mouse vertebrae are presented to successfully demonstrate the feasibility of the method for low quality images.

Abstract - This paper presents an approach for solving the geometric image deformation problem due to lens distortion, using B-Spline surfaces. The calibration method is described and experimental results are presented for a close range photogrammetry setup with an "off-the-shelf' CCD video camera and a 3D calibration frame. Active light sources, optical fibers, were used as calibration points. The design of the calibration frame was a result of experimenting with different light emitting diodes, background lighting, and optical fibers.

A method was developed for the 3-D measurement of the skeletal alignment of both lower extremities under weight-bearing conditions. The method is based on the use of a positioning and calibration frame (Questor Precision Radiograph), a standardized patient positioning protocol and precision radiography. The bony alignment is represented by a cahbrated stick- figure diagram in frontal, lateral and vertical projections. It is supplemented by a list of angular and linear measurements of importance for planning corrective orthopaedic surgery and for evaluating their results.

The parameters p of analytical elements in space (straight lines, circles, spheres, cylinders, etc.) are determined by minimizing the distance between the rays related to a contour of an element in the images and the element in space itself. The coordinates of a contour assigned to an element are determined with subpixel accuracy using a complex filter algorithm, which automatically follows a line. The proposed method does not need marks on the object to calculate the desired parameters. Hence it is especially suited for quality control in industrial applications.

We consider one-photogram raster-photogrammetry to be highly suitable for robot-vision applications. To date a Zeiss-Jena UMK 10/1318 metric camera and projector have been used. The metric projector is a high-precision instrument, whose interior orientation is known with the same accuracy as that of the metric camera. The equipment projects a reticule consisting of a double series of straight lines intersecting in nodes on the object to be photographed. In normal case where the metric camera and projector optical axes are parallel to one another and normal to the base, the image of the reticule on the photogram,id est the raster will be distorted but the horizontal reticule lines remain horizontal and equidistant, and the nodes only move on the horizontal lines. Consequently, in order to plot one node, it is merely sufficient to measure one coordinate on the raster photogram. If the image that is obtainable with the camera is analysed on-line with a RS1 Rollsimetric Reseau-Scanning System, which allows automatic extraction and measurement of the marked points, on-line plotting can be obtained.

The survey of the geometrical parameters controlling the orientation and spatial frequency of the joints outcropping on rock walls is the starting procedure to assess the geomechanical behaviour of the rock mass. This is of particular importance in the case of civil and mining engineering applications, when high and steep rock scarps are to be monitored. Within the problem of monitoring geostructural discontinuities on a rock slope by photogrammetric facilities, image processing are becoming more and more important. In particular, Digital Terrain Model procedures implemented on analytical plotters, when enhanced with a certain software, allows the survey of the joint sets which characterize the local rock mass conditions. After a theoretical discussion of the method proposed, the paper reports the results obtained for a real rock slope. The photogrammetric acquired data are compared with direct measurements by using the conventional field survey methods. The good agreement between calculated and measured values shows that photogrammetric techniques are a powerful tool for rock slope characteri- zation and monitoring.

Collocation is a powerful technique in filtering the correlated part of a signal from noise. It is now a day widely applied in many research field (e.g. in Geodesy to estimate the geoid or in Photogrammetry to reconstruct a DEM). In this paper a 3-D collocation filter is developed from the theoretical and numerical point of view. The main theoretical problem, i.e. to find a suitable catalogue of positive definite functions, is solved and a proper set of positive definite functions for a 3-D process is defined; futhermore a package of FORTRAN 77 programs is developed to implement the method. To test this stochastic filter, a simulated 3-D signal was computed; the numerical procedure has proved to be effective.

Reversed Engineering of a Product Model (RPM) is a theoretical model whereby a series of high definition CCD camera images are taken of an existing facility. Through these images and an interactive CAD system, a CAD model can be created. This paper will concentrate on the basic research and tasks required to accomplish the RPM model. The research falls into two primary areas. These are (Phase 1) Image Capture; Input Image Coordinates, Control and Scale, and (Phase 2) Design and Implementation of a CAD system. The tasks for Phase 1 breakdown as follows: 1) determine method to position the camera; 2) determine lighting configuration; 3) determine common shapes and features to be considered; 4) determine pre- treatment of images before viewing; 5) determine method of viewing; 6) study how to reconstruct 3D model from 3 or more 2-D views; 7) study how to store; present and manipulate images; 8) compute image coordinate systems; 9) study the conversion of the bit-mapped data to graphics data. The tasks for Phase 2 breakdown as follows: 1) determine the requirements of the CAD system; 2) determine whether an existing CAD system can be used; 3) design and implement the CAD system.

During the development of vehicles body-shapes with the lowest possible air-resistance are the goal of wind-tunnel experimentation. Aerodynamic features are invetigated and body-shapes are geometrically measured in order on the one hand, to document current vehicle geometry, whilst on the other, providing data on body-shape to facilitate numerical streamlining and body-shape optimisation. Photogrammetry has opened up the possibility of rapide and extensive geometrical measurement of vehicles in the wind-tunnel. The basis for this measurement method is a new approach multiple-image-matching which enables analysis on a digital basis. Employing this algorithm a new measure- ment system with great industrial potential is being developed. For the first time in the course of this project high resolution CCD-sensors with up to 7 million pixels per image for photogrammetric on-line-imaging are being used.

S. Vittore in Ciel d' Oro's dome has been surveyed with photogrammetry in two different and far-off periods :first the intrados and second the extrados. Here are related analytical approaches and methods used to make mutual relation between two separated restitutions to get sections, thicknesses and geometry for right analysis and static test. Than we get a deeper study of description methods with three-dimensional models (-)f. the dome. At last are reported metric and qualitative considerations.

We present algorithms for locating polyhedral objects using three edge points. An edge point is a three-dimensional data point which lies on a known edge of an object. However, the precise position of an edge point on an edge is unconstrained. In general, with three edge points, we have to solve a system of nonlinear equations. However, there are special cases, where we can solve the location problems analytically. The special cases depend on the collinearity and coplanarity of the three edge points.

A system for automatic correlation based on the analitical stereoplotter Digicart 40 is presented. A multistep approach to the problem of the least square matching is discussed. The application to the automatic D.T.M. compilation is described with the results obtained.

This paper deals with using feature-based matching, FBM, to automatically accomplish the correspondence for conjugate points in a stereopair then to determine the relative orientation parameters. The approach includes : (1) coarse matching between a reduced image pairs by FBM to determine the affine transformation coefficients for patch prediction, (2) matching critical points in the corresponded patches, and (3) calculating relative orientation parameters and performing consistency check. In the first two steps, FBM is applied. Which includes (1) convolving each image with a Laplacian of Gaussian, LoG, mask, (2) vectorizing the zero crossing image, (3) performing line approximation to extract critical points, and (4) similarity assessment. An aerial stereopair was used in the case study. To improve the matching accuracy, the refinement for the image correspondence by area-based matching, ABM, is also studied. The results indicate that the RMS of Y-parallax is 0.8 pixels by FBM and is 0.25 pixels after the correspondence refinement.

This paper reports a triangulation based measuring system which has applicability to the increasing demand for close range measurement data. This system uses a linear sensor array and diode laser light source and is discussed with respect to theory, calibration and practical results. An analysis of the use of this profiler to acquire spatial information (e.g. wriggle surveys, refurbishment) and local information (e.g. deformation) is given. Consideration is given to: errors from setting up, establishing a datum, profile position, and the inherent errors particular to triangulation systems.

The surveyor or dmImentalist of ancient Egyptian monuments and excavations almost always meet the problem of registering the decorated walls and wall-fragments of Pharaonic buildings. This job has been usually done by direct copying of pictures and hieroglyphs onto transparent foil even today. This process is inaccurate, slow and it can only register relatively little information; in addition, it is a very time-consuming work.4 The use of photo9rammetry can basically improve this process: the spatial model of photographed surfaces can be viewed at any time, and you can also make accurate measurements on the photos. Thus, the actual state can be preserved and reconstructed even if the original is destroyed. A computerized documentation of originals can be made by a computer-assisted interactive graphical system based on digital models. This system provides more information than the traditional drawings made after pho- togrammetric interpretation. This documentation is detailed, accurate, and the draw- ings can be stored on magnetic data carriers. On the basis of stored data, the plots can be displayed at any scale and in colour according to their thematic content; var- ious metric data can be retrieved and drawn by a computer-controlled plotter. With the use of special graphical programmes the corresponding walls or figures on wall-frag- ments can be matched, certain elements /e.g. hieroglyphs/ can be defined, and the figures or writings on walls can be completed or reconstructed by using known repre- sentations and texts. By transforming the photogrammetric pictures, scale-true images can be produced, from which the wall representations can be mounted together. A Hungarian expedition of Ebtvos Lorand University /Budapest/, led by Professor Lasz- 16 Kakosy has been excavating tomb No. 32 in Thebes, Egypt since 1983. The author was a member of this expedition with scholarship between 11 January and 11 April, 1988, made photogrammetric pictures on the walls and wall-fragments of the tomb in order to ease their archaeological documentation. By November-December 1989 most part of the tomb was interpreted with the application of computer-assisted photogrammetric methods; in addition, the digital drawings of walls were also produced at scale 1: 5. These drawings were compared to the walls on the site in March 1990 with the collaboration of Egyptologists; the plots were cor- rected and completed accordingly. At present, the necessary improvement of the digi- tal map-making system has been going on at the Institute of Geodesy, Cartography and Remote Sensing /IGCRS/, which has developed the programme.

The article presents the author's experiences in image processing for aerial photographs. Some aspects of smoothing filters, edge detection and line vectorization for linear features are discussed. In an attempt to obtain an appropriate raster image for the line vectorization, various smoothing filters and edge detection algorithms are compared. For the line vectorization, the Hough Transform method is presented.

The subject under discussion describes the complite measurement of the locations of the various historical relics, especially of the 188 satellite tombs within the Zhaoling mausoleum of Emperor Taizong of Tang Dynasty, using multilayer and multitemporal remote sensing informations, with the comprehensive utilization of the photogrammetric and remote sensing technique, and combining the comprehensive analysis of the archaeological investigating materials. 37 ruins of the graves had been newly found. And 1:4 to 1:25,000 scale map series for locating and measuring the shapes of the Zhaolilng various cultural relics have been complited. The whole data have been digitalization-pro- cessed. The first data base of Zhaoling cultural relics in China has been established.

The effects of the graininess of the photographic emulsion on the radiometric noise of the digital data are investigated, particu- larly the degradation of the precision of point matching in stereo pairs. For small pixel sizes, e.g. 7.5 pm in the new Zeiss digiti- zer, the radiometric noise due to graininess can amount to more than 20 per cent of signal. In contrast to that the radiometric noise of a directly rasterizing CCD-camera usually is only a few thousands of the signal.

This paper describes a procedure that deals with the on-line stereo measurement of multi-media images. This method is able to trace the ray from the object point to the image point through refracting surfaces between different media. The geometric paramters of the surfaces as well as the refraction indices are part of the orientation data. Hence a functional correction of the refraction effects in the image plane will be unnecessary. At first the equation describing the ray tracing are explained briefly, followed by a description of the integration of the algorithms into the Loop-program of the analytical plotter Zeiss Planicomp C100. By means of an example with plane refracting surfaces the advantages of this procedure will be shown in contrast to the solution working with functional correction in the image plane.

Within the context of a research project at the Institute for Photogrammetry and Image Processing of the University of Braunschweig in collaboration with the Orthopaedic Clinic of the University of Bonn, Department of Biomechanics/Biophysics, the applicability and medical relevance of 3D surface measurement procedures to determine scoliotic deformity is tested. The purpose of this paper is to give an introduction in this special problem and show the first practical experiences.

The extensions to new fields and the advances in speed and comprehensiveness in currently reported close range photogrammetry have been mainly derived by adaptation of classical methods. Information is extracted from sets of two dimensional recorded "images", often, nowadays, after increasingly sophisticated image processing. The improvement in accuracy and reliability of the resulting information, however extensive the image processing, is still limited by any physical shortcomings in the processing of the incoming photonic signals before and during the recording stage. As better analysis becomes possible, previously adequate techniques for acquisition of data may impose critical limitations. This contribution re-examines some of the fundamental aspects of the physical interactions of alternative photonic systems with object surfaces, optical systems and recording media, in their resulting effects on the resolution, accuracy and reliability of the recorded data and on the information derived from the records. Some examples are included of specific work that has established a basis for a better understanding of some often unsuspected possibilities for improvement of performance. A brief review will be included of current developments related to topics introduced in the author's paper in the Symposium in Stockholm in 1978

A collaborative project to understand the interaction of microwave altimeter and scatterometer signals from the ERS-1 satellite with short gravity-capillary waves is being undertaken. Part of this work involves deriving sea surface statistics, by the automated stereo-matching of stereo photographic pairs of water images, based on an adaptive least squares sheet growing algorithm. This approach avoids the manual processing of stereo images, which has until now limited the oceanographic application of stereo photography. Results of the automated matching process are presented together with the high frequency sea surface micro-topography and the corresponding power spectral density for a stereo photographic pair of images obtained by Holthuijsen (1983) from helicopter-mounted platforms.

The paper gives a review of applied and potential algorithms for estimating approximate values before the bundle adjustment of close-range data: This estimation is mainly considered a problem of solving polynomial equations. Some general approaches to the polynomial solution problem as treated in numerical mathematics are given. There is also a discussion of particular photogrammetric estimation methods and their polynomial formulation. The discussion provides a basis for making decision on method of estimating approximate values in the various situations met in close-range photogrammetry.

The principle of the "camera-on-theodolite" calibration method is reviewed; no control field is required. Standard procedures and algorithms are presented for routine use of the method. The relevant image processing algorithms are described in detail. A sub-pixel shift method is proposed for assessment of the accuracy of target image location. The calibration results are analysed and the issue of the usability of the calibrated parameters is discussed. Using motorised theodolites, the method is particularly useful for fully automated calibration.

The two-stage matching method can be used to improve the result of digital image correlation . Choosing the best matching target size which is decided by the range of the peak of central target area can increase the effects in the practical use . The Fast Fourier Transformation (FFT) method presented herein is a very fast and rigorous method of the image matching The main advantage of FFT method is its computational efficiency. It requires , for the computation of the image matching for all interested points , the FFT method provides the means for spectral and correlation analysis between target sizes and results of the matching. A comparison of the two-stage and FFT methods is given which involves theories,procedures ,processing times,and matching precision. Various statistical tests are performed in order to diagnose possible systematic effects.

In order to adapt the pilot's pressure mask individually there is a need to evaluate the topography of the human face. Classical shadow moire technique was combined with modern digital image processing to insure the capability of the developed system to automatically trace the location of the full and half multiples of moire fringes. Use of digital image processing allows depth measurements not only at those fringe locations, but also at the fractional fringe position, thus one can use less dense fringe patterns. Such patterns are more easily adapted for automated processing. The developed software and hardware are capable to acquire the image, digitize it and calculate the 3D location for any point in the area of interest, with plane resolution of 0.5 mm and depth resolution of 0.3 mm. The developed approach can be modified to work on a variety of surface topologies, which require fast and automated analysis with the digital output transferred to a cutting device.

We propose a pattern recognition system based on an architecture close to the one found in human visual cortex which is called Hypercolumns. We use this discrete parametric representation in connection with a sparsley coding associative memory. In principle the application of such a representation appears to be very well suited for data reduction and pattern recognition processes and is part of a neural instruction set [2].

The recent development of CCD-cameras and powerful PC's allows the step from analogue to digital photogrammetry, especially for close range applications. At the Department of Photogrammetry and Cartography at the Technical University of Berlin a completely digital system for image acquisition and evaluation has been designed and realized in an experimental hardware and software configuration. The mobile PC-controlled image acquisition module works with one or two CCD- cameras to provide stereo images. The digital imagery is stored on hard disk and can subsequently be evaluated using various image processing techniques (e.g. image matching for automatic coordinate measurement). The hardware and software components of the current system are presented and some application examples concerning the measurement of rough and textured surfaces like rock or soil are discussed to demonstrate the actual system performance.

A projected moire method was realized with image analysis software on a PC/framegrabber configuration. A CCD camera was used for evaluation of paper prints, transparencies or film negatives obtained from photographic moire. Video sequences could be studied using a camcorder and slide projector. The resolution of the CCD was sufficient for a static depth resolution between moire fringes of 10 mm in a field of 60x40 cm. Steps of image analysis were: multiplication of reference grid with distorted line picture, Sobel filtering, unidirectional mean filter. Anatomical landmarks, or predefined points on the moire fringes were marked interactively; from the binarized image, coordinates were extracted directly, or transferred to AutoCAD. 3-D reconstructions and measurements of fringe curvature thus became possible. The method's reduced sensitivity makes it robust, versatile and inexpensive, but quite capable of quantitative studies on the body surface, with the subject in a position at will. Examples are given for the documentation and evaluation of postural problems of musicians, of children at ballet school, and of physiotherapy.

The basic relationship of object surface reconstruction by the approach of FAST Vision (= facets stereo vision) is nonlinear. For solution a Taylor series expansion and the iterative Newton- Gauf3 procedure may be used. However, rather precise starting values for the object surface parameters have to be supplied. Two procedures will be presented: object lifting (for use for surface spots) and art adopted image pyramid from multiresolution image processing.

The use of finite element modeling for the study of implant-bone systems is a valuable method for improving the design of new implants. However the cumberson modeling of the anatomic geometries has been limiting the accuracy of the models, regarding the geometry as well as the material properties. It was the purpose of the present project to generate almost automatically a FEM model from stacked CT-scans of long bones and to assign to every element the material properties according to the local density. An interface program was written which detects the inner and outer contours of the cortical bone on every scan, joins them together to build up subvolumes and transfers them in vector format into the FEM package I-DEAS. The sub- volumes are smaller units of a model, which allow to control the meshing. After the automatic mesh generation within I- DEAS, the elements are read back to the interface program, where each one is assigned the material properties corresponding to the local density of the element location in the cortical or spongy bone. Besides of the generation of FE models it is possible to generate solid models of the scanned bones which may be used for display purpose or the simulation of implantations. It is now possible, to create detailed models of long bones within a short time and to use not only standard or average bone properties but individual values that may vary strongly, for example in the case of osteoporosis.

Accuracy estimation is often a necessary requirement in many applications of close range photogrammetry. In general, three methods are available for use. These are: (1). Error propagation by using algebraic expressiOns. (2). Error propagation by using numerical partial differentiation. (3). Error estimation by use of Monte Carlo simulation. All three methods are used in accuracy estimation on a simulated model data in close range photogrammetry. The consistancy of results point to the validity of each procedure, considered individually. Often, the sources of errors due to base and focal length are neglected. The current study indicates that the combined effect is usually significant and hence should not be neglected. An extension of the study into the topic of variance reduction in data analyses is included. In particular, the rather difficult control variable technique is adapte to the close range case. The computer programs developed in this study are being extended to cover stratified sampling and use of complementary random numbers.

Industrial measuring systems have a chance for permanent use only if they prove their worth in everyday application. If the initial apprehension of a non-geodetic client about photogrammetry as a measuring method is put aside, a broad spectrum of applications is opened. Measurements in the construction control of power-stations belong today mainly to the category of "quality control:. The demands on the measuring device used on-site, the temporal duration of a measurement and the achievable quality level re accordingly high. Using two examples of projects (measurement of a chimney: measurement of the section tube of a hydroelectric power-station), boundary conditions, the measuring process and the results obtained will be presented and compared.

The possibility to digitize large image formats in partial images by means of CCD-matrix sensors on-line are offered by the principle of reseau-scanning. The close to the image plane placed reseau enables to combine the partial images to an entire image. Precondition for the application of this technique is to handle object recording and reseau projection separately. The con- ception of the RSC and the algorithms, which are used for the point determination in the digital image are presented. First measurements show a precision in the object space of about 1:75000.

Photogrammetric and Image processing are used in evaluating aircraft accidents and occurrences. Requirements for this necessitates the ability to evaluate any form of imagery such as metric, non-metric, realtime and near realtime video images, including non-conventional images from xray, and other non optical images. This paper describes areas of application, and results of using conventional photogrammetry and video images for real scene data and video animation of the photogrammetric data.

At the University of Essen an analytical imaging and processing system for motion analysis .has been developed (Motography). This article presents some examples of applications in sports and medicine, which have been performed in collaboration with the Department for functional morphology of the University of Bochum.

The Determination of the threedimensional distribution of joint - systems is necessary for forecasting and analysis of the stability, of water- or gaspenetration and of more parameters in mining and rock mechanics. The measurements are performed by analytical instrumentation with on- line analysis and interpretation and graphical enhancement by CAD systems.

A number of researchers have recently described algorithms to automatically compute the aspect graph representation of objects. To date, research in this area has been limited to entirely rigid objects of various different shape classes. We present a generalization of the aspect graph concept which can be applied to objects defined as articulated assemblies of rigid parts.

This paper describes research into a new integrated robot vision system and manipulator controller. The technique uses a combination of stereoscopic vision using standard television cameras, structured lighting and photogrammetry to obtain the relative three dimensional positions of a robot manipulator and a target object. The manipulator is then moved towards the object using the vision system to provide feedback of the manipulator position. Having shown that it is possible to apply photogrammetric techniques to real time robot manipulator control the emphasis of the research has been directed to the use of non standard imaging devices, ie linescan cameras, for the data collection.

Analytical and close-range photogrammetry is used for strata deformation and subsidence study over underground mining excavation with chief objective of quick analysis. This paper describes methodology and results of planar movement measurement of a large number of points fixed over physical model by analytical exploitation of the projective correspondence between the frontal plane of the model and plane of photographs, taken over different stages of workings. Taking the advantage of synoptic view of this technique, the monitoring of subsidence over active underground excavation was also done to cut short on-site measuring time and to avoid error due to additional movement during observation period. Five camera stations were designed in a row at 100 m distance from the row of measuring pillars to cover the panel of 270 m x 100 m dimension.

In this paper, an idea is proposed concerning the Geometric Three Dimensional Model (GTDM). Through examples, the whole process of setting up the model and its adaptability are demonstrated. Using the method of GTDM for image understanding makes it possible to effectively extract information on random distributed goal. Thus, this is of advantage to the work in the following three areas: (1) To identify the implicit information of the air remote sensing images; (2) To discuss the visual computational theory used for non-generalized cone objects; (3) To develop the accurate guidance technique based on pattern matching.

This paper deals with the testing method and its relevant theory on the determination of the deformation of the bridge-model with a CCD solid state camera. It includes real-time positioning and surveying system with a CCD solid state camera, data preprocessing, photogrammetric processing and the test of determining the deformation of the bridge-model in real time.

The technology of determining the external shape of the coolig tower, using a photogrammetric method along tangent line of the observation radiuses with the real shape are presented. The determination procedure of the theoretical shape is discribed in the project. Some basic technologies are presented and the examples of their application in chosen polish cooling towers of various size are given.

Photogrammetric collinearity conditions are used directly for image coordinates where corresponding gray values are then differenced for least squares image matching. In this way, geometric and radiometric parameters related to forming of stereoscopic images are unified in a functional model. Matching between multiple images and si- multaneous object space positioning for points given as grid nodes has been found practicable. In terms of spatial intersection, we discover that hierarchic approaches to improving approximations can be well applied to reconstruction of a digital surface model, with image displacements being in the order of 12 pixels. At last, some ideas about further developments of our matching with .positioning algorithm are remarked. Key words: generation of digital surface models, at once matching and positioning, 2-photo versus 4-photo cases

Markov Random Field(MRF) model is a very useful model for image texture processing. But its stability condition is hardly to meet for natural textures. To find a stable MRF model is difficult and complex in computation. In this paper a new MRF model, called Modified Markov Random Field Model, is proposed; A stable Modified MRF model can be easily obtained for stochastic and natural textures. It is suitable for texture synthesis and data compression.

Moire projection method enables non-contact measurement of the shape or deformation of different surfaces and constructions by fringe pattern analysis. The fringe map aquisition of the whole surface of the object under test is one of the main adventage comparing with "point by point" methods. The computer analyzes the shape of the whole surface and next user can select different points or cross sections of the object map. Instananeous image recoquition gives another advantage, measurement of transient events e.g. during technical process. In this paper will be presented a few typical examples of an application of the moire projection techique in solving different medical problems. Equipment for determining posture defects using moire projection onto a CCD camera will be described. Because the analysis of moire images by conventional methods is tedious the moire fringe is digitized and analysed in real time using a phase stepping method. The technique has been applied experimentally for the analysis of osseo-muscular deformities. For this purpose the equipment was installed in The Rehabilitation Clinic for Children and Youth in Katowice.

We present two well-known statistical methods here to extract features related to different lung diseases on the chest X-ray images: 1).Texture feature; 2). Moment parameter feature. 11 parameters of texture feature and 7 moment parameters among many others were chosen to represent the characteristics of three different lung diseases which are frequently encountered in routine clinical diagnoses and as features for further recognition use. At the recognition step, the K-means algorithm based on the least-square function was employed as a classifier to distinguish 18 samples based on those parameters. Recognition rates from about 70% to 100% are achieved according to different diseases.

Segmentation and detection of object points on non-textured surfaces are one of the basic image processing processes in some photogrammetric applications. In this paper, we approach this problem in two steps. 1). A local thresholding process is applied which detects local maximum contrast. From this we get a primary segmented binary image. 2). Several contour tracing and thinning processes followed which in the meantime remove noises and the traced circles whose perimeters lie outside an interactively given range. Thus almost all the object points are detected. The whole procedure can be controlled interactively based on certain a priori knowledge and application requirements. This approach has demonstrated good performance with application to images taken from the photogrammetric test field at the institute.

The paper reviews the problems involved in the calibration of photog- rammetric solid-state camera stations and especially describes a method for the continuous online calibration of such a station. In this proce- dure the orientations of the CCD cameras of the station are continuous- ly checked under working conditions by utilizing image matching techni- ques and calibrated reference coordinates. The system is installed in a pilot system working in a car factory. Both simulation and practical results on the performance capabilities are given.